|
Low voltage lighting
Low-voltage is
a type of outdoor lighting that uses 12 volt instead of the
common household 110/120 volts. Low-voltage is energy-efficient,
and also cheap and easy to install – a reason that explains its
increasing popularity.
Be careful, anyway: use low-voltage outdoor lighting
parsimoniously, only and where necessary. And do not forget
controls (timers, photocells...) that can be used to avoid
light
pollution.
Low-voltage
outdoor kits
There are many
pre-packaged kits with all the correspondent components:
- the transformer (or power back),
- cables and
- fixtures.
Kits are often
conceived to be expanded: you can add lights in the future as
necessary, or you can purchase a second (and a third…) kit to
expand your system.
Prices
There are
low-voltage outdoor lighting kits for all prices. Prices of some
inexpensive kits range from $15 to $100, but the best ones are
$300 and more. It all depends on the number and type of fixtures
and materials. Be aware: low prices usually mean low quality and
non-friendly environmental solutions.
Lamps
The low voltage
lamps are, obviously, the kit’s source of light. Lamps can be of
very different types and watts. Halogen lamps are the most
common and the ones presented in most kits, but the market is
beginning to offer low voltage fluorescent, which are much more
energy efficient and environmentally-friendly.
Obviously, you
should use lights rated for outdoor use: see
Compact Fluorescent Lamps.
Fixtures
Outdoor
lighting fixtures should be rated as water-resistant and for
outdoor use.
There are many options concerning low-voltage fixtures, with
endless styles, most of them of low quality and source of light
pollution.
The best options are qualified fixtures of
Energy Star,
European Union Eco-label, or fixtures supported by
organizations as the
The
International Dark Sky Association
or the Underwriters
Laboratories), even if they involve higher
initial costs. They are a guarantee of quality and durability,
and are environmentally friendly products.
Transformers
(Power-Backs) and outlets
 Low-voltage
transformers supply the electricity and are conceived to plug
into standard outlets in order to reduce the 110/120 volts
household current to just 12 volts. Many transformers, even the
cheaper, have automatic timers in order to switch lights on/off
at preset times. Configurations are variable, but even cheaper
and common 100-watt transformers have a manual on/off switch and
an automatic timer.
The outlets
used by transformers are usually outdoor ones, but it can also
be indoor outlets (just be sure that the transformer is rated
for inside use and there is enough space around it, in order to avoid
heat negative side effects).
There are
several options concerning transformers and their capacities.
The number of garden lights/fixtures that can be connected to a
particular transformer depends on its capacity and on the total
wattage demanded by the fixtures. If the transformer is, say,
100-watt, then the total wattage of the lights should not exceed
100 watts (10 garden lights with 10-watt bulbs, for instance).
In the
above example, if you wanted to install 20 lights or 30
lights (instead of 10) you could purchase a second/third
transformer… The alternative to these standard packages, is to buy a
bigger transformer and configure a less standardized system: the
size of transformer, in this case, depends on the number of
light fixtures you may want to install...
Some basic calculations will be needed, in this case. If, for
instance, you intend to install 10 path lights of 18 watts (180
W) and 2 down-lighting lights of 50 W (100 W) then you will need
a 300-watt transformer – or a larger one to allow future
expansions (the extra wattage should
not exceed one-third of the total needs, anyway). Typically,
transformers can range from 150 W to 900 W.
Low voltage cable
The low voltage
cable transmits the electricity. Low voltage cable must be
weather-resistant. Typically they
begin and end at the transformer (creating a
looped run).
Popular sizes include 12-, 14- and
16-gauge (gauge depends on the amount of watts required to
operate the system). Typically 16-gauge cable can carry 150
watts, while 14-gauge cable can carry 200 watts and 12-gauge
(the standard wire gauge) cable can carry 300 watts.
Installation & Low-voltage outdoor lighting
Some pre-packaged
low-voltage systems are relatively simple and safe to install and may not
demand a professional electrician.
Take into account some basic design techniques. See:
Landscape lighting design.
See also:
House Lighting Basics
Low-voltage
outdoor lighting kits;
Outdoor solar lighting
Controls & lighting:
timers, motion-sensors, photosensors and dimmers
Back to top Low-Voltage Outdoor Lighting
Return to
Energy Savings Home Page
|
